Display device

ABSTRACT

Provided is a display device including a display panel including light emitting regions and a non-light emitting region adjacent to the light emitting regions, a first insulation layer disposed on the display panel, the first insulation layer having a first refractive index, and having first openings defined in a region overlapping the light emitting regions, a second insulation layer covering the display panel and the first insulation layer and having a second refractive index greater than the first refractive index of the fist insulation layer, a third insulation layer disposed on the second insulation layer, the third insulation layer having the first refractive index, and having second openings defined in a region overlapping the light emitting regions, and a fourth insulation layer covering the second insulation layer and the third insulation layer and the fourth insulation layer having the second refractive index.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a divisional application of U.S. patent application Ser. No.16/886,039 filed May 28, 2020 (now pending), the disclosure of which isincorporated herein by reference in its entirety. U.S. patentapplication Ser. No. 16/886,039 claims priority to and benefits ofKorean Patent Application No. 10-2019-0079385 under 35 U.S.C. § 119,filed in the Korean Intellectual Property Office (KIPO) on Jul. 2, 2019,the entire contents of which are incorporated herein by reference.

BACKGROUND (a) Technical Field

The disclosure herein relates to a display device having improved lightefficiency.

(b) Description of the Related Art

A display device may be categorized into a self-light-emitting typedisplay device in which a light emitting element emits light by itselfand a light-receiving type display device which controls thetransmittance of received light. A self-light-emitting type displaydevice may be, for example, an organic light emitting display device.Light generated in a light emitting layer of an organic light emittingdisplay device may be emitted in the lateral direction as well as in thefront direction. Light efficiency may be determined based on lightemitted in the front direction. That is, light emitted in the lateraldirection may cause a deterioration in light efficiency.

It is to be understood that this background of the technology sectionis, in part, intended to provide useful background for understanding thetechnology. However, this background of the technology section may alsoinclude ideas, concepts, or recognitions that were not part of what wasknown or appreciated by those skilled in the pertinent art prior to acorresponding effective filing date of the subject matter disclosedherein.

SUMMARY

The disclosure provides a display device having improved lightefficiency.

An embodiment provides a display device including a display panelincluding a plurality of light emitting regions and a non-light emittingregion adjacent to the plurality of light emitting regions, a firstinsulation layer disposed on the display panel, the first insulationlayer having a first refractive index, and having a plurality of firstopenings defined in a region overlapping the plurality of light emittingregions, a second insulation layer covering the display panel and thefirst insulation layer and having a second refractive index greater thanthe first refractive index of the first insulation layer, a thirdinsulation layer disposed on the second insulation layer, the thirdinsulation layer having the first refractive index and having aplurality of second openings defined in a region overlapping theplurality of light emitting regions, and a fourth insulation layercovering the second insulation layer and the third insulation layer andthe fourth insulation layer having the second refractive index.

In an embodiment, each of the second insulation layer and the fourthinsulation layer may overlap the plurality of first openings on a plane.

In an embodiment, the first refractive index may be in a range of about1.45 to about 1.55, and the second refractive index may be in a range ofabout 1.65 to about 1.80.

In an embodiment, the first insulation layer and the third insulationlayer may include a first organic matter, and the second insulationlayer and the fourth insulation layer may include a second organicmatter different from the first organic matter.

In an embodiment, the first organic matter may include an acrylic resin.

In an embodiment, the second organic matter may include zirconia.

In an embodiment, a thickness of the first insulation layer may be in arange of about 1.5 μm to about 5 μm, and a maximum thickness of thesecond insulation layer may be in a range of about 3 μm to about 20 μm.

In an embodiment, the first insulation layer may include a firstthrough-surface defining each of the plurality of first openings, and anangle between the first through-surface and a surface on which the firstinsulation layer is disposed may be in a range of about 60° to about80°.

In an embodiment, an absolute value of the difference between a width ofeach of the plurality of first openings and a width of each of theplurality of light emitting regions may be about 3 μm or less.

In an embodiment, the display device may further include a fifthinsulation layer disposed on the fourth insulation layer, the fifthinsulation layer having the first refractive index, and having aplurality of third openings defined in a region overlapping theplurality of light emitting regions, and a sixth insulation layercovering the fourth insulation layer and the fifth insulation layer andhaving the second refractive index.

In an embodiment, the plurality of second openings may be extended in afirst direction and spaced apart in a second direction crossing thefirst direction on a plane, and the plurality of third openings may beextended in the second direction and spaced apart in the first directionon the plane.

In an embodiment, the display device may further include an inputsensing layer between the display panel and the first insulation layer.

In an embodiment, a display device includes a display panel including aplurality of light emitting regions and a non-light emitting regionadjacent to the plurality of light emitting regions, a first insulationlayer disposed on the display panel, the first insulation layer having afirst refractive index, and having a first opening overlapping thenon-light emitting region, a second insulation layer covering thedisplay panel and the first insulation layer and having a secondrefractive index less than the first refractive index of the firstinsulation layer, a third insulation layer disposed on the secondinsulation layer, having the first refractive index, and having a secondopening overlapping the non-light emitting region, and a fourthinsulation layer covering the second insulation layer and the thirdinsulation layer and the fourth insulation layer having the secondrefractive index.

In an embodiment, the second insulation layer and the fourth insulationlayer may overlap the first opening on a plane.

In an embodiment, the first refractive index may be in a range of about1.45 to about 1.55, and the second refractive index may be in a range ofabout 1.1 to about 1.3.

In an embodiment, the first insulation layer and the third insulationlayer may include a first organic matter, and the second insulationlayer and the fourth insulation layer may include a second organicmatter.

In an embodiment, the first organic matter may include porous zirconia.

In an embodiment, the second organic matter may include a porous acrylicresin.

In an embodiment, a thickness of the first insulation layer may be in arange of about 1.5 μm to about 5 μm, and a maximum thickness of thesecond insulation layer may be in a range of about 3 μm to about 20 μm.

In an embodiment, the first insulation layer may include a firstthrough-surface defining the first opening, and an angle between thefirst through-surface and the display panel may be in a range of about90° to about 120°.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the disclosure, and are incorporated in and constitutea part of this specification. The drawings illustrate embodiments and,together with the description, serve to explain principles of thedisclosure. In the drawings:

FIG. 1 is a perspective view of a display device according to anembodiment;

FIG. 2A to FIG. 2E are schematic cross-sectional views of a displaydevice according to an embodiment;

FIG. 3 is a plan view of a display panel according to an embodiment;

FIG. 4 is schematic diagram of an equivalent circuit of a pixel PXaccording to an embodiment;

FIG. 5 is a schematic cross-sectional view illustrating a portion of theconfiguration of a display panel according to an embodiment;

FIG. 6 is a plan view illustrating a portion of a display panel and aportion of an optical layer according to an embodiment;

FIG. 7 is a schematic cross-sectional view taken along line I-I′ of FIG.6 ;

FIG. 8 is a schematic cross-section of a region corresponding to theregion taken along line I-I′ of FIG. 6 ;

FIG. 9 is a plan view illustrating a portion of a display panel and aportion of an optical layer both according to an embodiment;

FIG. 10 is a schematic cross-sectional view taken along line II-II′ ofFIG. 9 ;

FIG. 11 is a schematic cross-sectional view taken along line III-III′ ofFIG. 9 ;

FIG. 12 is a schematic cross-sectional view of a region corresponding tothe region taken along line I-I′ of FIG. 6 ;

FIG. 13 is a plan view of an input sensing layer according to anembodiment;

FIG. 14 is a plan view of illustrating an enlarged view of region AA ofFIG. 13 ; and

FIG. 15 is a schematic cross-sectional view of a region taken along lineIV-IV′ of FIG. 14 .

DETAILED DESCRIPTION OF THE EMBODIMENTS

Although the disclosure may be modified in various manners and haveadditional embodiments, embodiments are illustrated in the accompanyingdrawings and will be mainly described in the specification. However, thescope of the disclosure is not limited to the embodiments in theaccompanying drawings and the specification and should be construed asincluding all the changes, equivalents and substitutions included in thespirit and scope of the disclosure.

Some of the parts which are not associated with the description may notbe provided in order to describe embodiments and like reference numeralsrefer to like elements throughout the specification.

In the disclosure, when an element (or a region, a layer, a portion,etc.) is referred to as being “on,” “connected to,” or “coupled to”another element, it means that the element may be directly disposedon/connected to/coupled to the other element, or that a third elementmay be disposed therebetween.

Like reference numerals refer to like elements. In the drawings,thicknesses, ratios, and dimensions of elements may be exaggerated foran effective description of technical contents and for clarity.

Further, in the specification, the phrase “in a plan view” means when anobject portion is viewed from above, and the phrase “in a schematiccross-sectional view” means a schematic cross-section taken byvertically cutting an object portion is viewed from the side.Additionally, the terms “overlap” or “overlapped” mean that a firstobject may be above or below or to a side of a second object, and viceversa. Additionally, the term “overlap” may include layer, stack, faceor facing, extending over, covering or partly covering or any othersuitable term as would be appreciated and understood by those ofordinary skill in the art. The terms “face” and “facing” mean that afirst element may directly or indirectly oppose a second element. In acase in which a third element intervenes between the first and secondelement, the first and second element may be understood as beingindirectly opposed to one another, although still facing each other.When an element is described as ‘not overlapping’ or ‘to not overlap’another element, this may include that the elements are spaced apartfrom each other, offset from each other, or set aside from each other orany other suitable term as would be appreciated and understood by thoseof ordinary skill in the art.

The term “and/or” includes all combinations of one or more of whichassociated configurations may define.

It will be understood that, although the terms “first”, “second”, etc.may be used herein to describe various elements, these elements shouldnot be limited by these terms. These terms are only used to distinguishone element from another. For example, a first element could be termed asecond element, and, similarly, a second element could be termed a firstelement, without departing from the scope of embodiments. The terms of asingular form may include plural forms unless the context clearlyindicates otherwise.

In addition, terms such as “below,” “lower,” “above,” “upper,” and thelike may be used to describe the relationship of the configurationsshown in the drawings. However, these terms are used as a relativeconcept and although described with reference to the direction indicatedin the drawings, embodiments are not limited thereto.

“About” or “approximately” as used herein is inclusive of the statedvalue and means within an acceptable range of deviation for theparticular value as determined by one of ordinary skill in the art,considering the measurement in question and the error associated withmeasurement of the particular quantity (i.e., the limitations of themeasurement system). For example, “about” may mean within one or morestandard deviations, or within ±30%, 20%, 5% of the stated value.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which the disclosure pertains. It isalso to be understood that terms defined in commonly used dictionariesshould be interpreted as having meanings consistent with the meanings inthe context of the relevant art, and are expressly defined herein andwill not be interpreted in an ideal or excessively formal sense unlessclearly defined in the specification.

It should be understood that the terms “comprise”, “include” and “have”are intended to specify the presence of stated features, integers,steps, operations, elements, components, or combinations thereof in thedisclosure, but do not preclude the presence or addition of one or moreother features, integers, steps, operations, elements, components, orcombinations thereof.

Hereinafter, embodiments will be described with reference to theaccompanying drawings.

FIG. 1 is a perspective view of a display device according to anembodiment.

Referring to FIG. 1 , a display device DD may be used for largeelectronic devices such as a television, monitor, and an externaladvertisement board, and also for small-and medium-sized electronicdevices such as a personal computer, a notebook computer, a personaldigital terminal, a vehicle navigation system unit, a game machine, aportable electronic apparatus, and a camera. It should be understood,however, that these are merely examples, and the display device DD maybe incorporated in other electronic apparatuses without departing fromthe spirit and scope of the disclosure.

In the display device DD, a display region DA and a non-display regionNDA may be defined.

The display region DA on which an image IM is displayed may be parallelto a surface defined by a first direction DR1 and a second directionDR2. The normal direction of the display region DA, that is, thethickness direction of the display device DD may be indicated by a thirddirection DR3. The front surface (or an upper surface) and the rearsurface (or a lower surface) of each member may be distinguished by thethird direction DR3. The third direction DR3 may be a direction crossingthe first direction DR1 and the second direction DR2. For example, thefirst direction DR1, the second direction DR2, and the third directionDR3 may be perpendicular to each other.

Meanwhile, directions indicated by the first to third directions DR1,DR2, and DR3 are relative. They may be converted to or represented bydifferent directions. Hereinafter, a first direction to a thirddirection refer to the same directions indicated by the first to thirddirection DR1, DR2, and DR3, respectively, and refer to the samereference numerals. In the specification, a surface defined by the firstdirection DR1 and the second direction DR2 is defined as a plane, and“plan view” or the like may refer to a view shown from the thirddirection DR3.

The non-display region NDA is a region adjacent to the display regionDA, and may be a region on which the image IM is not displayed. A bezelregion of the display device DD may be defined by the non-display regionNDA.

The non-display region NDA may surround the display region DA. However,the embodiment is not limited thereto. The shape of the display regionDA and the shape of the non-display region NDA may be varied in otherembodiments.

FIG. 2A to FIG. 2E are schematic cross-sectional views of a displaydevice according to an embodiment. FIG. 2A to FIG. 2E illustrate a crosssection depicted in the second direction DR2 and the third directionDR3. FIG. 2A to FIG. 2E are illustrated to describe the laminationrelationship of functional members that may constitute the displaydevice DD.

The display device DD according to an embodiment may include a displaypanel, an optical layer, an anti-reflector, and a window. At least someof the display panel, the optical layer, the anti-reflector, and thewindow may be formed by a continuous process, or at least some thereofmay be coupled to each other through an adhesive member. FIG. 2A to FIG.2E exemplarily illustrate an optically transparent adhesive member OCAas the adhesive member. The adhesive member described hereinafter mayinclude a typical adhesive or a typical pressure sensitive adhesive. Inan embodiment, the anti-reflector and the window may be substituted byother components, or may be omitted.

As illustrated in FIG. 2A, the display device DD may include a displaypanel DP, an optical layer OPL, an anti-reflection panel RPP, and awindow panel WP.

The display panel DP may generate the image IM (see FIG. 1 ). Thedisplay panel DP according to an embodiment may be a light-emitting typedisplay panel, but is not particularly limited thereto. For example, thedisplay panel DP may be an organic light emitting display panel or aquantum dot light emitting display panel. A light emitting layer of anorganic light emitting display panel may include an organic lightemitting material. A light emitting layer of a quantum dot lightemitting display panel may include a quantum dot, a quantum rod, and thelike. Hereinafter, the display panel DP is described as an organic lightemitting display panel.

The optical layer OPL may be disposed on the display panel DP. Theoptical layer OPL may change the path of light emitted from the displaypanel DP.

The anti-reflection panel RPP may reduce the reflectance of externallight incident from an upper side of the window panel WP. Theanti-reflection panel RPP according to an embodiment may include a phaseretarder and a polarizer. The phase retarder may be of a film type or aliquid crystal coating type, and may include a λ/2 phase retarder and/ora λ/4 phase retarder. The polarizer may also be of a film type or aliquid crystal coating type. The film type polarizer may include astretchable synthetic resin film, and the liquid crystal coating typepolarizer may include liquid crystals arranged in a predeterminedarrangement. The phase retarder and the polarizer may include aprotective film. The phase retarder and the polarizer themselves or theprotective film may be defined as a base layer of the anti-reflectionpanel RPP.

The anti-reflection panel RPP according to an embodiment may includecolor filters. The color filters may have a predetermined arrangement.The arrangement of the color filters may be determined in considerationof the light-emitting colors of pixels included in the display panel DP.The anti-reflection panel RPP may include a black matrix adjacent to thecolor filters.

The anti-reflection panel RPP according to an embodiment may include anoffset-interference structure. For example, the offset-interferencestructure may include a first reflection layer and a second reflectionlayer disposed on different layers. A first reflected light and a secondreflected light respectively reflected from the first reflection layerand the second reflection layer may be offset-interfered, andaccordingly, external light reflectance may be reduced.

The window panel WP according to an embodiment may include a base layerWP-BS and a light-blocking pattern WP-BZ. The base layer WP-BS mayinclude a glass substrate and/or a synthetic resin film. The base layerWP-BS is not limited to a single layer. The base layer WP-BS may includetwo or more films or layers bonded by the adhesive member.

The light-blocking pattern WP-BZ may overlap or partially overlap thebase layer WP-BS. The light-blocking pattern WP-BZ may be disposed onthe rear surface of the base layer WP-BS. The light-blocking patternWP-BZ may substantially define the non-display region NDA of the displaydevice DD. A region on which the light-blocking pattern WP-BZ is notdisposed may define the display region DA of the display device DD.

The light-blocking pattern WP-BZ may have a multi-layered structure. Themulti-layered structure may include a color layer and a light-blockinglayer. The color layer may have a color, and the light blocking layermay be in black. The color layer and the light-blocking layer may beformed, for example, through deposition, printing, and coatingprocesses. Although not separately illustrated, the window panel WP mayfurther include a functional coating layer disposed on the front surfaceof the base layer WP-BS. The functional coating layer may include, forexample, an anti-fingerprint layer, an anti-reflection layer, a hardcoating layer, and the like.

Referring to FIG. 2B to FIG. 2E, the display device DD may include aninput sensing sensor. In FIG. 2B to FIG. 2E, among the input sensingsensor, the anti-reflector, and the window, a component formed through acontinuous process with another component may be referred to as a layer.Among the input sensing sensor, the anti-reflector, and the window, acomponent bonded to another component through the adhesive member may bereferred to as a panel. A panel may include a base layer which providesa base surface, for example, a synthetic resin film, a compositematerial film, a glass substrate, and the like, but a layer may not havethe base layer. In other words, the elements and or members referred toas a layer or layers may be disposed on a base layer which may beprovided by or comprised of other elements and or members.

Hereinafter, depending on the presence of a base layer, the inputsensing sensor, the anti-reflector, and the window may be respectivelyreferred to as an input sensing panel ISP, the anti-reflection panelRPP, and the window panel WP, or an input sensing layer ISL, ananti-reflection layer RPL, and a window layer WL.

As illustrated in FIG. 2B, the display device DD may include the displaypanel DP, the input sensing layer ISL, the optical layer OPL, theanti-reflection panel RPP, and the window panel WP. The input sensinglayer ISL may be disposed between the display panel DP and the opticallayer OPL. The input sensing layer ISL may obtain the coordinateinformation of an external input (for example, a touch event).

Between the optical layer OPL and the anti-reflection panel RPP, andbetween the anti-reflection panel RPP and the window panel WP, theoptically transparent adhesive member OCA may be disposed.

In FIG. 2C to FIG. 2E, the window panel WP and the window layer WL areillustrated without the distinction of the base layer WP-BS and thelight-blocking pattern WP-BZ.

As illustrated in FIG. 2C to FIG. 2D, the display device DD may includethe display panel DP, the optical layer OPL, the input sensing panelISP, the anti-reflection panel RPP, and the window panel WP. Thelamination order of the input sensing panel ISP and the anti-reflectionpanel RPP is not limited to the embodiments shown in the drawings, butmay be changed.

As illustrated in FIG. 2E, the display device DD may include the displaypanel DP, the input sensing layer ISL, the optical layer OPL, theanti-reflection panel RPP, and the window layer WL. Compared to thedisplay device DD illustrated in FIG. 2B, the optically transparentadhesive members OCA may be omitted, and the input sensing layer ISL,the optical layer OPL, the anti-reflection layer RPL, and the windowlayer WL may be formed through a continuous process. The laminationorder of the input sensing layer ISL and the anti-reflection layer RPLis not limited to the embodiments shown in the drawings, but may bechanged.

FIG. 3 is a plan view of a display panel according to an embodiment.

Referring to FIG. 3 , the display panel DP may include a driving circuitGDC, a signal lines SGL (hereinafter, signal lines), signal pads DP-PD(hereinafter, signal pads), and pixels PX (hereinafter, pixels).

A display region DP-DA of the display panel DP may be defined as aregion on which the pixels PX are disposed. The display region DP-DA ofthe display panel DP may be a region corresponding to the display regionDA (see FIG. 1 ) of the display device DD (see FIG. 1 ), and anon-display region DP-NDA of the display panel DP may be a regioncorresponding to the non-display region NDA (see FIG. 1 ) of the displaydevice DD (see FIG. 1 ).

The driving circuit GDC may include a scan driving circuit. The scandriving circuit generates scan signals, and may sequentially output thescan signals to scan lines SL.

The scan driving circuit may include thin film transistors formedthrough the same process as that of a driving circuit of the pixels PX,for example, a Low Temperature Polycrystalline Silicon (LTPS) process ora Low Temperature Polycrystalline Oxide (LTPO) process.

The signal lines SGL may include the scan lines SL, data lines DL, apower line PL, light emitting control lines ECL, and a control signalline CSL.

Each of the scan lines SL is connected to a corresponding one of thepixels PX. Each of the data lines DL is connected to a corresponding oneof the pixels PX. The power line PL is connected to the pixels PX. Eachof the light emitting control lines ECL is connected to a correspondingone of the pixels PX. The control signal line CSL may provide controlsignals to the scan driving circuit. Although the power line PL isdescribed as singular in this embodiment, it may be plural in otherembodiments.

The signal lines SGL may overlap the display region DP-DA and thenon-display region DP-NDA. The signal lines SGL may include a pad unitand a line unit. The line unit may overlap the display region DP-DA andthe non-display region DP-NDA. The pad unit may be disposed at an end ofthe line unit. The pad unit may be disposed in the non-display regionDP-NDA, and may overlap a corresponding signal pad among the signal padsDP-PD. In the non-display region DP-NDA, a region in which the signalpads DP-PD are disposed may be defined as a pad region DP-PA. A circuitboard (not shown) may be connected to the pad region DP-PA.

FIG. 4 is schematic diagram of an equivalent circuit of a pixel PXaccording to an embodiment. FIG. 4 illustrates the pixel PX connected toan i^(th) scan line SLi and an i^(th) light emission control line ECLi.

The pixel PX may include an organic light emitting diode OLED and apixel circuit CC. The pixel circuit CC may include transistors T1 to T7and a capacitor CP. The pixel circuit CC may control the amount ofcurrent flowing through the organic light emitting diode OLED inaccordance with a data signal.

The organic light emitting diode OLED may emit light of a predeterminedluminance in accordance with the amount of current provided from thepixel circuit CC. To this end, the level of a first power ELVDD may beset to be higher than the level of a second power ELVSS.

Each of the transistors T1 to T7 may include an input electrode (or asource electrode), an output electrode (or a drain electrode), and acontrol electrode (or a gate electrode).

A first electrode of a first transistor T1 may be connected to the powerline PL via a fifth transistor T5. The power line PL may provide thefirst power ELVDD to the first electrode of the first transistor T1 viathe fifth transistor T5. A second electrode of the first transistor T1may be connected to an anode electrode of the organic light emittingdiode OLED via a sixth transistor T6.

The first transistor T1 may control the amount of current flowingthrough the organic light emitting diode OLED in accordance with avoltage applied to a control electrode of the first transistor T1.

A second transistor T2 may be connected between the data line DL and thefirst electrode of the first transistor T1. A control electrode of thesecond transistor T2 may be connected to an i^(th) scan line SLi. Thesecond transistor T2 may be turned on when an i^(th) scan signal isprovided to the i^(th) scan line SLi to electrically connect the dataline DL and the first electrode of the first transistor T1.

A third transistor T3 may be connected between the second electrode ofthe first transistor T1 and the control electrode of the firsttransistor T1. A control electrode of the third transistor T3 may beconnected to the i^(th) scan line SLi. The third transistor T3 may beturned on when the i^(th) scan signal is provided to the i^(th) scanline SLi to electrically connect the second electrode of the firsttransistor T1 and the control electrode of the first transistor T1.Accordingly, when the third transistor T3 is turned on, the firsttransistor T1 may be connected in the form of a diode.

A fourth transistor T4 may be connected between a node ND and aninitialization power generating unit (not shown). A control electrode ofthe fourth transistor T4 may be connected to an i-1^(st) scan lineSLi-1. The fourth transistor T4 may be turned on when an i-1^(st) scansignal is provided to the i-1^(st) scan line SLi-1 to provide aninitialization voltage Vint to the node ND.

A fifth transistor T5 may be connected between the power line PL and thefirst electrode of the first transistor T1. A control electrode of thefifth transistor T5 may be connected to an i^(th) light emission controlline ECLi.

A sixth transistor T6 may be connected between the second electrode ofthe first transistor T1 and the anode electrode of the organic lightemitting diode OLED. A control electrode of the sixth transistor T6 maybe connected to the i^(th) light emission control line ECLi.

A seventh transistor T7 may be connected between the initializationpower generating unit (not shown) and the anode electrode of the organiclight emitting diode OLED. A control electrode of the seventh transistorT7 may be connected to an i+1^(st) scan line SLi+1. The seventhtransistor T7 may be turned on when an i+1^(st) scan signal is providedto the i+1^(st) scan line SLi+1 to provide the initialization voltageVint to the anode electrode of the organic light emitting diode OLED.

The seventh transistor T7 may improve the capability of the blackexpression or display by the pixel PX. For example, when the seventhtransistor T7 is turned on, a parasitic capacitor (not shown) of theorganic light emitting diode OLED is discharged. Then, when blackluminance is implemented or the pixel PX displays black, the organiclight emitting diode OLED does not emit light due to leakage currentfrom the first transistor T1, and accordingly, the capability ofexpressing or displaying black may be improved.

Additionally, FIG. 4 illustrates the control electrode of the seventhtransistor T7 being connected to the i+1^(st) scan line SLi+1, but thedisclosure is not limited thereto. In other embodiments, the controlelectrode of the seventh transistor T7 may be connected to the i^(th)scan line SLi or the i-1^(st) scan line SLi-1.

Although FIG. 4 illustrates PMOS transistors by way of example, theembodiment is not limited thereto. In another embodiment, the pixelcircuit CC may include NMOS transistors. In another embodiment, thepixel circuit CC may be formed of a combination of NMOS and PMOStransistors.

The capacitor CP may be disposed between the power line PL and the nodeND. The capacitor CP may store a voltage corresponding to a data signal.When the fifth transistor T5 and the sixth transistor T6 are turned onin accordance with the voltage stored in the capacitor CP, the amount ofcurrent flowing through the first transistor T1 may be determined. Inthe disclosure, an equivalent circuit of the pixel PX is not limited tothe equivalent circuit illustrated in FIG. 4 .

FIG. 5 is a schematic cross-sectional view illustrating a portion of theconfiguration of a display panel according to an embodiment.

Referring to FIG. 5 , the display panel DP may include a base layer BL,a circuit layer ML, a pixel definition film PDP, a light emittingelement layer EL, and an encapsulation layer TFE.

The base layer BL may include a synthetic resin film. A synthetic resinlayer may be formed on a work substrate used in manufacturing thedisplay panel DP. Thereafter, a conductive layer, an insulation layer,and the like may be formed on the synthetic resin layer. After the worksubstrate is removed, the synthetic resin layer may correspond to thebase layer BL. The synthetic resin layer may include a thermosettingresin. For example, the synthetic resin layer may be a polyimide-basedresin layer, but the material thereof is not limited thereto. The baselayer BL may include an organic/inorganic composite material substrateand the like.

The circuit layer ML may include the driving circuit GDC, the signallines SGL, and the signal pads DP-PD of FIG. 3 . FIG. 5 illustrates someof the components of the circuit layer ML. The circuit layer ML mayinclude a transistor TR and insulation layers BFL, L1, L2, L3, and L4.

An insulation layer BFL is disposed on the base layer BL, and thetransistor TR may be disposed on the insulation layer BFL. Thetransistor TR of FIG. 5 may be the first transistor T1 illustrated inFIG. 4 . The transistor TR may include a semiconductor layer ACL, acontrol electrode GED, a first electrode ED1 and a second electrode ED2.

The semiconductor layer ACL may be disposed on the insulation layer BFL.The insulation layer BFL may be a barrier layer for protecting a lowersurface of the semiconductor layer ACL. The insulation layer BFL mayblock contaminants or moisture in the base layer BL from penetratinginto the semiconductor layer ACL or contaminants or moisture in theoutside from penetrating into the semiconductor layer ACL through thebase layer BL. In an embodiment, the insulation layer BFL may beselectively disposed or omitted.

The semiconductor layer ACL includes a semiconductor material. Thesemiconductor material may be selected from amorphous silicon,polysilicon, a metal oxide semiconductor, and a combination thereof.

A first insulation layer L1 may be disposed on the insulation layer BFL,and may cover the semiconductor layer ACL. The first insulation layer L1may include an organic material or an inorganic material.

The control electrode GED may be disposed on the first insulation layerL1. A second insulation layer L2 may be disposed on the first insulationlayer L1, and may cover the control electrode GED. The second insulationlayer L2 may include an inorganic material. In an embodiment, the secondinsulation layer L2 may be omitted.

A third insulation layer L3 may be disposed on the second insulationlayer L2. The first electrode ED1 and the second electrode ED2 may bedisposed on the third insulation layer L3. The first electrode ED1 andthe second electrode ED2 may be connected to the semiconductor layer ACLthrough through-holes passing through the first insulation layer L1, thesecond insulation layer L2, and the third insulation layer L3.

A fourth insulation layer L4 may be disposed on the third insulationlayer L3, and may cover the first electrode ED1 and the second electrodeED2. The fourth insulation layer L4 may be formed of a single layer ormultiple layers. For example, the single layer may include an organiclayer. The multiple layers may be provided by laminating an organiclayer and an inorganic layer. The fourth insulation layer L4 may be aplanarization layer for providing a flat surface on an upper portionthereof.

The pixel definition film PDP and the light emitting element layer ELmay be disposed on the fourth insulation layer L4.

The pixel definition film PDP may be disposed on the circuit layer ML.An opening OP may be defined in the pixel definition film PDP. A lightemitting region PXA may be defined in a region in which light isgenerated in the organic light emitting diode OLED (see FIG. 3 ). In theembodiment, the light emitting region PXA may be defined in a regioncorresponding to the opening OP. The opening OP may expose at least aportion of a first electrode E1. The display panel DP may include anon-light emitting region NPXA in which light is not generated. Thenon-light emitting region NPXA may be a region which is not the lightemitting region PXA.

The light emitting element layer EL may include the first electrode E1,a light emitting layer EM, and a second electrode E2. The light emittingelement layer EL may correspond to the organic light emitting diode OLEDdescribed with reference to FIG. 4 .

The first electrode E1 may be disposed on the fourth insulation layerL4, and may be electrically connected to the second electrode ED2through a through-hole defined in the fourth insulation layer L4. Thefirst electrode E1 may correspond to the anode electrode of the organiclight emitting diode OLED described with reference to FIG. 4 .

The light emitting layer EM may be disposed between the first electrodeE1 and the second electrode E2. The light emitting layer EM may have asingle-layered structure having a single layer formed of a singlematerial, or a multi-layered structure having layers formed of differentmaterials.

The light emitting layer EM may include an organic material. The organicmaterial is not particularly limited as long as it is a material in therelevant art. For example, the light emitting layer EM may be formed ofat least one of materials emitting red, green, and blue colors, and mayinclude a fluorescent material or a phosphorescent material.

The second electrode E2 may be disposed on the light emitting layer EMand the pixel definition film PDP. The second electrode E2 may receivethe second power ELVSS (see FIG. 4 ).

The encapsulation layer TFE may be disposed on the second electrode E2.Although not illustrated, a capping layer for covering the secondelectrode E2 may be disposed between the encapsulation layer TFE and thesecond electrode E2. The encapsulation layer TFE may directly cover thecapping layer.

The encapsulation layer TFE may include a first inorganic layer ECL1, anorganic layer ECL2, and a second inorganic layer ECL3 sequentiallylaminated. The organic layer ECL2 may be disposed between the firstinorganic layer ECL1 and the second inorganic layer ECL3. The firstinorganic layer ECL1 and the second inorganic layer ECL3 may be formedby depositing an inorganic material, and the organic layer ECL2 may beformed by depositing, printing, or coating an organic material.

The first inorganic layer ECL1 and the second inorganic layer ECL3 mayinclude at least one of silicon nitride, silicon oxy nitride, siliconoxide, titanium oxide, and aluminum oxide. The organic layer ECL2 mayinclude a polymer, for example, an acrylic organic layer. However, thisis only an example, and the embodiment is not limited thereto.

FIG. 5 illustrates the encapsulation layer TFE including two inorganiclayers and one organic layer, but the embodiment is not limited thereto.For example, the encapsulation layer TFE may include three inorganiclayers and two organic layers. For example, the encapsulation layer TFEmay have a structure in which the inorganic layers and the organiclayers are alternately laminated.

FIG. 6 is a plan view illustrating a portion of a display panel and aportion of an optical layer according to an embodiment, and FIG. 7 is aschematic cross-sectional view taken along line I-I′ of FIG. 6 .

Referring to FIG. 6 and FIG. 7 , the multiple light emitting regions PXAmay be provided. The light emitting regions PXA may be arranged along afourth direction DR4. The fourth direction DR4 may be a directionintersecting the first direction DR1 and the second direction DR2. Thelight emitting regions PXA may be arranged along a fifth direction DR5intersecting the fourth direction DR4. FIG. 6 illustrates each of thelight emitting regions PXA having the same area. However, the embodimentis not limited thereto. Each of the light emitting regions PXA accordingto an embodiment may have different areas.

The optical layer OPL may be disposed on the display panel DP. Theoptical layer OPL may include a first insulation layer IL1, a secondinsulation layer IL2, a third insulation layer IL3, and a fourthinsulation layer IL4.

The first insulation layer IL1 may be disposed on the display panel DP.The first insulation layer IL1 may include a first organic matter. Thefirst organic matter may include an acrylic resin. However, this is onlyan example. The first organic matter is not limited to the aboveexample.

The first insulation layer IL1 may have first openings defined in aregion overlapping the light emitting regions PXA. The first insulationlayer IL1 may have a mesh shape on a plan view. FIG. 7 illustrates onefirst opening OPa and a light emitting region PXA corresponding to thefirst opening OPa among the light emitting regions PXA.

The first insulation layer IL1 may have a first refractive index. Thefirst refractive index may be in a range of about 1.45 to about 1.55.The first insulation layer IL1 may have a thickness TK1 a in a range ofabout 1.5 μm to about 5 μm. The first insulation layer IL1 may include afirst through-surface SW-IL1 defining the first opening OPa. A minimumangle θ1 between the first through-surface SW-IL1 and a surface on whichthe first insulation layer IL1 is disposed may be in a range of about60° to about 80°. The surface on which the first insulation layer IL1 isdisposed may be an upper surface of the display panel DP.

The absolute value of the difference DS1 between the width WT-OPa of thefirst opening OPa and the width WT-PXA of the light emitting region PXAmay be about 3 μm or less.

The second insulation layer IL2 may cover the display panel DP and thefirst insulation layer IL1. The second insulation layer IL2 may includea second organic matter different from the first organic matter. Thesecond organic matter may include zirconia. However, this is only anexample. The second organic matter is not limited to the above example.The second insulation layer IL2 may have a second refractive index. Thesecond refractive index may be greater than the first refractive index.The second refractive index may be in a range of about 1.65 to about1.80. The second insulation layer IL2 may have a maximum thickness TK2 agreater than the thickness TK1 a of the first insulation layer IL1. Themaximum thickness TK2 a of the second insulation layer IL2 may be in arange of about 3 μm to about 20 μm. The second insulation layer IL2 mayoverlap the first opening OPa on a plane. The second insulation layerIL2 may be filled in the first opening OPa. The second insulation layerIL2 may provide a flat surface on an upper portion thereof.

The third insulation layer IL3 may be disposed on the second insulationlayer IL2. The third insulation layer IL3 and the first insulation layerIL1 may include the same material. The third insulation layer IL3 mayhave second openings defined in a region overlapping the light emittingregions PXA. In the embodiment, the third insulation layer IL3 and thefirst insulation layer IL1 may have the same shape on a plane. Forexample, on a plane, the third insulation layer IL3 may have a meshshape. FIG. 7 illustrates one second opening OPb and one light emittingregion PXA corresponding the second opening OPb among the light emittingregions PXA. The second opening OPb may overlap the first opening OPa ona plane.

The third insulation layer IL3 may have the first refractive index. Thethird insulation layer IL3 may have a thickness TK1 b in a range ofabout 1.5 μm to about 5 μm. The third insulation layer IL3 may include asecond through-surface SW-IL3 defining the second opening OPb. A minimumangle θ2 between the second through-surface SW-IL3 and a surface onwhich the third insulation layer IL3 is disposed may be in a range ofabout 60° to about 80°. The surface on which the third insulation layerIL3 may be disposed may be an upper surface of the second insulationlayer IL2.

The absolute value of the difference between the width WT-OPb of thesecond opening OPb and the width WT-PXA of the light emitting region PXAmay be about 3 μm or less. FIG. 7 illustrates a case in which thedifference between the width WT-OPb of the second opening OPb and thewidth WT-PXA of the light emitting region PXA is about zero.

The fourth insulation layer IL4 may cover the second insulation layerIL2 and the third insulation layer IL3. The fourth insulation layer IL4may include the second organic matter. The fourth insulation layer IL4may have the second refractive index. The fourth insulation layer IL4may have a maximum thickness TK2 b greater than the thickness TK1 b ofthe third insulation layer IL3. The maximum thickness TK2 b of thefourth insulation layer IL4 may be in a range of about 3 μm to about 20μm. The fourth insulation layer IL4 may overlap each of the firstopening OPa and the second opening OPb on a plane. The fourth insulationlayer IL4 may be filled in the second opening OPb. The fourth insulationlayer IL4 may provide a flat surface on an upper portion thereof.

For ease of explanation, FIG. 7 illustrates a first light LT1 and aseparate second light LT2 according to the path of light generated inthe light emitting layer EM. The first light LT1 and the second lightLT2 may be emitted in the lateral direction. The first light LT1 may beprovided to the third insulation layer IL3 from the light emitting layerEM. The first light LT1 may be refracted or reflected in the thirddirection DR3 from the second through-surface SW-IL3 due to therefractive index difference between the third insulation layer IL3 andthe fourth insulation layer IL4 and the minimum angle θ2 between thesecond through-surface SW-IL3 and the surface on which the thirdinsulation layer IL3 is disposed. When the minimum angle θ2 between thesecond through-surface SW-IL3 and the surface on which the thirdinsulation layer IL3 is disposed is less than about 60° or greater thanabout 80°, the first light LT1 may not be refracted or reflected in thethird direction DR3. However, this is only an example. In an embodiment,the first light LT1 may be provided to the first insulation layer IL1from the light emitting layer EM. The first light LT1 may be refractedor reflected in the third direction DR3 from the first through-surfaceSW-IL1 due to the refractive index difference between the firstinsulation layer IL1 and the second insulation layer IL2 and the minimumangle θ1 between the first through-surface SW-IL1 and the surface onwhich the first insulation layer IL1 is disposed. When the minimum angleθ1 between the first through-surface SW-IL1 and the surface on which thefirst insulation layer IL1 is disposed is less than about 60° or greaterthan about 80°, the first light LT1 may not be refracted or reflected inthe third direction DR3. The second light LT2 may be light having anincident path toward a lower surface of the third insulation layer IL3.The second light LT2 may be reflected from the lower surface of thethird insulation layer IL3 due to the refractive index differencebetween the second insulation layer IL2 and the third insulation layerIL3. Accordingly, the second light LT2 may not be visible from theoutside.

According to the disclosure, light emitted from the light emitting layerEM of the display device DD (see FIG. 1 ) may be refracted or reflecteddue to the refractive index difference between the first insulationlayer IL1 and the second insulation layer IL2, between the secondinsulation layer IL2 and the third insulation layer IL3, and between thethird insulation layer IL3 and the fourth insulation layer IL4, so thata light path may be changed. For example, the light path may be changedin the third direction DR3 or in a direction close to the thirddirection DR3, or in a direction in which the light is not visible. Dueto the changed light path, the light emitting efficiency of the displaydevice DD (see FIG. 1 ) may be improved and the straightness of thelight in a front direction may be improved. Accordingly, the disclosuremay provide a display device DD (see FIG. 1 ) having improved lightefficiency.

FIG. 8 is a schematic cross-section of a region corresponding to theregion taken along line I-I′ of FIG. 6 . The same reference numerals aregiven to the elements described with reference to FIG. 6 and FIG. 7 ,and the descriptions thereof are omitted.

Referring to FIG. 8 , an optical layer OPL-1 may be disposed on thedisplay panel DP. The optical layer OPL-1 may include a buffer layerBFL-1, an interlayer insulation layer IL-C, the first insulation layerIL1, the second insulation layer IL2, the third insulation layer IL3,the fourth insulation layer IL4, a fifth insulation layer IL5, and asixth insulation layer IL6.

The buffer layer BFL-1 may be disposed on the encapsulation layer TFE.The buffer layer BFL-1 may include an inorganic matter. For example, theinorganic matter may be silicon nitride. However, this is only anexample. In an embodiment, the buffer layer BFL-1 may be omitted.

The interlayer insulation layer IL-C may be disposed on the buffer layerBFL-1. The interlayer insulation layer IL-C may include an inorganicmatter. For example, the inorganic matter may be silicon nitride.However, this is only an example. In an embodiment, the interlayerinsulation layer IL-C may be omitted.

The fifth insulation layer IL5 may be disposed on the fourth insulationlayer IL4. The fifth insulation layer IL5 and the first insulation layerIL1 may include the same material. The fifth insulation layer IL5 mayhave third openings defined in a region overlapping the light emittingregions PXA. The fifth insulation layer IL5 may have a mesh shape on aplan view. FIG. 8 illustrates one third opening OPc and one lightemitting region PXA corresponding to the third opening OPc among thelight emitting regions PXA.

The fifth insulation layer IL5 may have a refractive index in a range ofabout 1.45 to about 1.55. The fifth insulation layer IL5 may have athickness TK1 c in a range of about 1.5 μm to about 5 μm. The fifthinsulation layer IL5 may include a third through-surface SW-IL5 definingthe third opening OPc. A minimum angle θ3 between the thirdthrough-surface SW-IL5 and a surface on which the fifth insulation layerIL5 is disposed may be in a range of about 60° to about 80°. The surfaceon which the fifth insulation layer IL5 may be disposed may be an uppersurface of the fourth insulation layer IL4.

The absolute value of the difference between the width WT-OPc of thethird opening OPc and the width WT-PXA of the light emitting region PXAmay be about 3 μm or less. FIG. 8 illustrates a case in which thedifference between the width WT-OPc of the third opening OPc and thewidth WT-PXA of the light emitting region PXA is about zero.

The sixth insulation layer IL6 may cover the fourth insulation layer IL4and the fifth insulation layer IL5. The sixth insulation layer IL6 mayhave a refractive index greater than the refractive index of the fifthinsulation layer IL5. The sixth insulation layer IL6 may have arefractive index in a range of about 1.65 to about 1.80. The sixthinsulation layer IL6 may have a maximum thickness TK2 c greater than thethickness TK1 c of the fifth insulation layer IL5. The maximum thicknessTK2 c of the sixth insulation layer IL6 may be in a range of about 3 μmto about 20 μm. The sixth insulation layer IL6 may overlap each of thefirst opening OPa, the second opening OPb, and the third opening OPc ona plane. The sixth insulation layer IL6 may be filled in the thirdopening OPc. The sixth insulation layer IL6 may provide a flat surfaceon an upper portion thereof.

For ease of explanation, FIG. 8 illustrates a first light LT1-1 and aseparate second light LT2-1 according to the path of light generated inthe light emitting layer EM. The first light LT1-1 and the second lightLT2-1 may be emitted in the lateral direction. The first light LT1-1 maybe provided to the fifth insulation layer IL5 from the light emittinglayer EM. The first light LT1-1 may be refracted or reflected in thethird direction DR3 from the third through-surface SW-IL5 due to therefractive index difference between the fifth insulation layer IL5 andthe sixth insulation layer IL6 and the minimum angle θ3 between thethird through-surface SW-IL5 and the surface on which the fifthinsulation layer IL5 is disposed. When the minimum angle θ3 between thethird through-surface SW-IL5 and the surface on which the fifthinsulation layer IL5 is disposed is less than about 60° or greater thanabout 80°, the first light LT1-1 may not be refracted or reflected inthe third direction DR3.

The second light LT2-1 may be light having an incident path toward alower surface of the fifth insulation layer IL5. The second light LT2-1may be reflected from the lower surface of the fifth insulation layerIL5 due to the refractive index difference between the fourth insulationlayer IL4 and the fifth insulation layer IL5. Accordingly, the secondlight LT2-1 may not be visible from the outside.

In other embodiments, light emitted from the light emitting layer EM ofthe display device DD (see FIG. 1 ) may be refracted or reflected due tothe refractive index difference between the fourth insulation layer IL4and the fifth insulation layer IL5 and the refractive index differencebetween the fifth insulation layer IL5 and the sixth insulation layerIL6, so that a light path may be changed. The fifth insulation layer IL5and the sixth insulation layer IL6 may refract or reflect light from thefifth insulation layer IL5 such that the light not refracted orreflected from the first insulation layer IL1 and the third insulationlayer IL3 may be refracted or reflected from the fifth insulation layerIL5. For example, the light path may be changed in the third directionDR3 or in a direction close to the third direction DR3, or in adirection in which the light is not visible. Due to the changed lightpath, the light emitting efficiency of the display device DD (see FIG. 1) may be improved and the straightness of the light in a front directionmay be improved. Accordingly, the light efficiency may be improved inthe display device DD (see FIG. 1 ).

FIG. 9 is a plan view illustrating a portion of a display panel and aportion of an optical layer according to an embodiment, and FIG. 10 is aschematic cross-sectional view taken along line II-II′of FIG. 9 . Thesame reference numerals are given to the elements described withreference to FIG. 6 to FIG. 8 , and the descriptions thereof areomitted.

Referring to FIG. 9 and FIG. 10 , an optical layer OPL-2 may be disposedon the display panel DP. The optical layer OPL-2 may include the bufferlayer BFL-1, the interlayer insulation layer IL-C, the first insulationlayer IL1, the second insulation layer IL2, a third insulation layerIL3-1, a fourth insulation layer IL4-1, a fifth insulation layer IL5-1,and a sixth insulation layer IL6-1.

The third insulation layer IL3-1 may be disposed on the secondinsulation layer IL2. The third insulation layer IL3-1 and the firstinsulation layer IL1 may be formed of the same material. The thirdinsulation layer IL3-1 may have second openings spaced apart in thefourth direction DR4 and extended in the fifth direction DR5intersecting the fourth direction DR4 on a plane. The third insulationlayer IL3-1 may have a stripe shape on a plan view. FIG. 10 illustratesone second opening OPd.

The third insulation layer IL3-1 may have a refractive index in a rangeof about 1.45 to about 1.55. The third insulation layer IL3-1 may have athickness TK1 b-1 in a range of about 1.5 μm to about 5 μm. The thirdinsulation layer IL3-1 may include a second through-surface SW-IL31defining the second opening OPd. A minimum angle θ21 between the secondthrough-surface SW-IL31 and a surface on which the third insulationlayer IL3-1 is disposed may be in a range of about 60° to about 80°. Thesurface on which the third insulation layer IL3-1 is disposed may be anupper surface of the second insulation layer IL2.

The fourth insulation layer IL4-1 may cover the second insulation layerIL2 and the third insulation layer IL3-1. The fourth insulation layerIL4-1 and the second insulation layer IL2 may be formed of the samematerial. The fourth insulation layer IL4-1 may have a refractive indexgreater than the refractive index of the third insulation layer IL3-1.The fourth insulation layer IL4-1 may have a refractive index in a rangeof about 1.65 to about 1.80. The fourth insulation layer IL4-1 may havea maximum thickness TK2 b-1 greater than the thickness TK1 b-1 of thethird insulation layer IL3-1. The maximum thickness TK2 b-1 of thefourth insulation layer IL4-1 may be in a range of about 3 μm to about20 μm. The fourth insulation layer IL4-1 may overlap each of the firstopening OPa and the second opening OPd on a plane. The fourth insulationlayer IL4-1 may be filled in the second opening OPd. The fourthinsulation layer IL4-1 may provide a flat surface on an upper portionthereof.

For ease of explanation, FIG. 10 illustrates a first light LT1-2 and aseparate second light LT2-2 according to the path of light generated inthe light emitting layer EM. The first light LT1-2 and the second lightLT2-2 may be emitted in the lateral direction. The first light LT1-2 maybe provided to the first insulation layer IL1 from the light emittinglayer EM. The first light LT1-2 may be refracted or reflected in thethird direction DR3 from the first through-surface SW-IL1 due to therefractive index difference between the first insulation layer IL1 andthe second insulation layer IL2 and the minimum angle θ1 between thefirst through-surface SW-IL1 and the surface on which the firstinsulation layer IL1 is disposed. When the minimum angle θ1 between thefirst through-surface SW-IL1 and the surface on which the firstinsulation layer IL1 is disposed is less than about 60° or greater thanabout 80°, the first light LT1-2 may not be refracted or reflected inthe third direction DR3. However, this is only an example. In anembodiment, the first light LT1-2 may be provided to the thirdinsulation layer IL3-1 from the light emitting layer EM. The first lightLT1-2 may be refracted or reflected in the third direction DR3 from thesecond through-surface SW-IL31 due to the refractive index differencebetween the third insulation layer IL3-1 and the fourth insulation layerIL4-1 and the minimum angle θ21 between the second through-surfaceSW-IL31 and the surface on which the third insulation layer IL3-1 isdisposed. When the minimum angle θ21 between the second through-surfaceSW-IL31 and the surface on which the third insulation layer IL3-1 isdisposed is less than about 60° or greater than about 80°, the firstlight LT1-2 may not be refracted or reflected in the third directionDR3.

The second light LT2-2 may be light having an incident path toward alower surface of the third insulation layer IL3-1. The second lightLT2-2 may be reflected from the lower surface of the third insulationlayer IL3-1 due to the refractive index difference between the secondinsulation layer IL2 and the third insulation layer IL3-1. Accordingly,the second light LT2-2 may not be visible from the outside.

FIG. 11 is a schematic cross-sectional view taken along line III-III′ ofFIG. 9 . The same reference numerals are given to the elements describedwith reference to FIG. 6 to FIG. 8 , and the descriptions thereof areomitted.

Referring to FIG. 9 to FIG. 11 , the fifth insulation layer IL5-1 may bedisposed on the fourth insulation layer IL4-1. The fifth insulationlayer IL5-1 and the first insulation layer IL1 may be formed of the samematerial. The fifth insulation layer IL5-1 may have third openingsspaced apart in the fifth direction DR5 and extended in the fourthdirection DR4 on a plane. The fifth insulation layer IL5-1 may have astripe shape on a plan view. FIG. 11 illustrates one third opening OPe.

The fifth insulation layer IL5-1 may have a refractive index in a rangeof about 1.45 to about 1.55. The fifth insulation layer IL5-1 may have athickness TK1 c-1 in a range of about 1.5 μm to about 5 μm. The fifthinsulation layer IL5-1 may include a third through-surface SW-IL51defining the third opening OPe. A minimum angle θ31 between the thirdthrough-surface SW-IL51 and a surface on which the fifth insulationlayer IL5-1 is disposed may be in a range of about 60° to about 80°. Thesurface on which the fifth insulation layer IL5-1 is disposed may be anupper surface of the fourth insulation layer IL4-1.

The sixth insulation layer IL6-1 may cover the fourth insulation layerIL4-1 and the fifth insulation layer IL5-1. The sixth insulation layerIL6-1 and the second insulation layer IL2 may be formed of the samematerial. The sixth insulation layer IL6-1 may have a refractive indexgreater than the refractive index of the fifth insulation layer IL5-1.The sixth insulation layer IL6-1 may have a refractive index in a rangeof about 1.65 to about 1.80. The sixth insulation layer IL6-1 may have amaximum thickness TK2 c-1 greater than the thickness TK1 c-1 of thefifth insulation layer IL5-1. The maximum thickness TK2 c-1 of the sixthinsulation layer IL6-1 may be in a range of about 3 μm to about 20 μm.The sixth insulation layer IL6-1 may overlap each of the first openingOPa and the third opening OPe on a plane. The sixth insulation layerIL6-1 may be filled in the third opening OPe. The sixth insulation layerIL6-1 may provide a flat surface on an upper portion thereof.

For ease of explanation, FIG. 11 illustrates a first light LT1-3 and aseparate second light LT2-3 according to the path of light generated inthe light emitting layer EM. The first light LT1-3 and the second lightLT2-3 may be emitted in the lateral direction. The first light LT1-3 maybe provided to the first insulation layer IL1 from the light emittinglayer EM. The first light LT1-3 may be refracted or reflected in thethird direction DR3 from the first through-surface SW-IL1 due to therefractive index difference between the first insulation layer IL1 andthe second insulation layer IL2 and the minimum angle θ1 between thefirst through-surface SW-IL1 and the surface on which the firstinsulation layer IL1 is disposed. When the minimum angle θ1 between thefirst through-surface SW-IL1 and the surface on which the firstinsulation layer IL1 is disposed is less than about 60° or greater thanabout 80°, the first light LT1-3 may not be refracted or reflected inthe third direction DR3. However, this is only an example. In anembodiment, the first light LT1-3 may be provided to the fifthinsulation layer IL5-1 from the light emitting layer EM. At this time,the first light LT1-3 may be refracted or reflected in the thirddirection DR3 from the third through-surface SW-IL51 due to therefractive index difference between the fifth insulation layer IL5-1 andthe sixth insulation layer IL6-1 and the minimum angle θ31 between thethird through-surface SW-IL51 and the surface on which the firstinsulation layer IL5-1 is disposed. When the minimum angle θ31 betweenthe third through-surface SW-IL51 and the surface on which the fifthinsulation layer IL5-1 is disposed is less than about 60° or greaterthan about 80°, the first light LT1-3 may not be refracted or reflectedin the third direction DR3.

The second light LT2-3 may be light having an incident path toward alower surface of the fifth insulation layer IL5-1. The second lightLT2-3 may be reflected from the lower surface of the fifth insulationlayer IL5-1 due to the refractive index difference between the fourthinsulation layer IL4-1 and the fifth insulation layer IL5-1.Accordingly, the second light LT2-3 may not be visible from the outside.

Light emitted from the light emitting layer EM of the display device DD(see FIG. 1 ) may be refracted or reflected due to the refractive indexdifference(es) among the first insulation layer IL1 to the sixthinsulation layer IL6, so that light path(s) may be changed. For example,the light path may be changed in the third direction DR3 or in adirection close to the third direction DR3, or in a direction in whichthe light is not visible. Due to the changed light path, the lightemitting efficiency of the display device DD (see FIG. 1 ) may beimproved and the straightness of the light in the front direction may beimproved. Accordingly, the display device DD (see FIG. 1 ) may haveimproved light efficiency.

FIG. 12 is a schematic cross-sectional view of a region corresponding tothe region taken along line I-I′ of FIG. 6 . The same reference numeralsare given to the elements described with reference to FIG. 6 and FIG. 7, and the descriptions thereof are omitted.

Referring to FIG. 12 , an optical layer OPL-3 may be disposed on thedisplay panel DP. The optical layer OPL-3 may include a first insulationlayer IL1-2, a second insulation layer IL2-2, a third insulation layerIL3-2, and a fourth insulation layer IL4-2.

The first insulation layer IL1-2 may be disposed on the display panelDP. The first insulation layer IL1-2 may include a first organic matter.In an embodiment, the first organic matter may include a porous acrylicresin. However, this is only an example. The first organic matter is notlimited to the above example. The first insulation layer IL1-2 may havefirst openings OPa-2 defined in a region overlapping the non-lightemitting region NPXA.

The first insulation layer IL1-2 may have a first refractive index. Forexample, the first refractive index may be in a range of about 1.45 toabout 1.55. The first insulation layer IL1-2 may have a thickness in arange of about 1.5 μm to about 5 μm. The first insulation layer IL1-2may include a first through-surface SW-IL12 defining the first openingOPa-2. A maximum angle θ4 between the first through-surface SW-IL12 anda surface on which the first insulation layer IL1-2 is disposed may bein a range of about 90° to about 120°. The surface on which the firstinsulation layer IL1-2 is disposed may be an upper surface of thedisplay panel DP.

The second insulation layer IL2-2 may cover the display panel DP and thefirst insulation layer IL1-2. The second insulation layer IL2-2 mayinclude a second organic matter different from the first organic matter.The second organic matter may include porous zirconia. However, this isonly an example. The second organic matter is not limited to the aboveexample. The second insulation layer IL2-2 may have a second refractiveindex. The second refractive index may be less than the first refractiveindex. For example, the second refractive index may be in a range ofabout 1.1 to about 1.3. The second insulation layer IL2-2 may have amaximum thickness TK2 a-2 greater than the thickness TK1 a-2 of thefirst insulation layer IL1-2. The maximum thickness TK2 a-2 of thesecond insulation layer IL2-2 may be in a range of about 3 μm to about20 μm. The second insulation layer IL2-2 may overlap the first openingOPa-2 on a plane. The second insulation layer IL2-2 may be filled in thefirst opening OPa-2. The second insulation layer IL2-2 may provide aflat surface on an upper portion thereof.

The third insulation layer IL3-2 may be disposed on the secondinsulation layer IL2-2. The third insulation layer IL3-2 and the firstinsulation layer IL1-2 may include the same material. The thirdinsulation layer IL3-2 may have a second opening OPb-2 defined in aregion overlapping the non-light emitting region NPXA.

The third insulation layer IL3-2 may have the first refractive index.The third insulation layer IL3-2 may have a thickness TK1 b-2 in a rangeof about 1.5 μm to about 5 μm. The third insulation layer IL3-2 mayinclude a second through-surface SW-IL32 defining the second openingOPb-2. A maximum angle θ5 between the second through-surface SW-IL32 anda surface on which the third insulation layer IL3-2 is disposed may bein a range of about 90° to about 120°. The surface on which the thirdinsulation layer IL3-2 is disposed may be an upper surface of the secondinsulation layer IL2-2.

The fourth insulation layer IL4-2 may cover the second insulation layerIL2-2 and the third insulation layer IL3-2. The fourth insulation layerIL4-2 and the second insulation layer IL2-2 may include the samematerial. The fourth insulation layer IL4-2 may have the secondrefractive index. The fourth insulation layer IL4-2 may have a maximumthickness TK2 b-2 greater than the thickness TK1 b-2 of the thirdinsulation layer IL3-2. The maximum thickness TK2 b-2 of the fourthinsulation layer IL4-2 may be in a range of about 3 μm to about 20 μm.The fourth insulation layer IL4-2 may overlap each of the first openingOPa-2 and the second opening OPb-2 on a plane. The fourth insulationlayer IL4-2 may be filled in the second opening OPb-2. The fourthinsulation layer IL4-2 may provide a flat surface on an upper portionthereof.

For ease of explanation, FIG. 12 illustrates a first light LT1-4 and aseparate second light LT2-4 according to the path of light generated inthe light emitting layer EM. The first light LT1-4 may be emitted in thelateral direction. The first light LT1-4 may be provided to the firstinsulation layer IL1-2 from the light emitting layer EM. The first lightLT1-4 may be refracted or reflected in the third direction DR3 from thefirst through-surface SW-IL12 due to the refractive index differencebetween the first insulation layer IL1-2 and the second insulation layerIL2-2 and the minimum angle θ4 between the first through-surface SW-IL12and the surface on which the first insulation layer IL1-2 may bedisposed. When the maximum angle θ4 between the first through-surfaceSW-IL12 and the surface on which the first insulation layer IL1-2 isdisposed is less than about 90° or greater than about 120°, the firstlight LT1-4 may not be refracted or reflected in the third directionDR3. However, this is only an example. In an embodiment, the first lightLT1-4 may be provided to the third insulation layer IL3-2 from the lightemitting layer EM. At this time, the first light LT1-4 may be refractedor reflected in the third direction DR3 from the second through-surfaceSW-IL32 due to the refractive index difference between the thirdinsulation layer IL3-2 and the fourth insulation layer IL4-2 and themaximum angle θ5 between the second through-surface SW-IL32 and thesurface on which the third insulation layer IL3-2 is disposed. When themaximum angle θ5 between the second through-surface SW-IL32 and thesurface on which the third insulation layer IL3-2 is disposed is lessthan about 90° or greater than about 120°, the first light LT1-4 may notbe refracted or reflected in the third direction DR3.

Light emitted from the light emitting layer EM of the display device DD(see FIG. 1 ) may be refracted or reflected due to the refractive indexdifference between the first insulation layer IL1-2 and the secondinsulation layer IL2-2 and the refractive index difference between thethird insulation layer IL3-2 and the fourth insulation layer IL4-2, sothat a light path may be changed. For example, the light path may bechanged in the third direction DR3 or in a direction close to the thirddirection DR3. Due to the changed light path, the light emittingefficiency of the display device DD (see FIG. 1 ) may be improved andthe straightness of the light in the front direction may be improved.Accordingly, the display device DD (see FIG. 1 ) may have improved lightefficiency.

FIG. 13 is a plan view of an input sensing layer according to anembodiment. The input sensing layer ISL to be described hereinafter maybe equally applied to the input sensing panel ISP (see FIG. 2C).

Referring to FIG. 13 , the input sensing layer ISL may include a sensingregion IS-DA corresponding to the display region DP-DA of the displaypanel DP illustrated in FIG. 3 and a line region IS-NDA corresponding tothe non-display region DP-NDA of the same.

The input sensing layer ISL may include first sensing electrodes EG1,second sensing electrodes EG2, a first signal line group SG1electrically connected to each or some corresponding electrodes amongthe first sensing electrodes EG1, a second signal line group SG2electrically connected to each of other electrodes, and a third signalline group SG3 electrically connected to the second sensing electrodesEG2.

FIG. 13 illustrates the first signal line group SG1 and the secondsignal line group SG2 being disposed having the sensing region IS-DAtherebetween. However, in an embodiment, the first signal line group SG1and the second signal line group SG2 may be disposed on the same side ofthe sensing region IS-DA. In other embodiments, each of the first signalline group SG1 and the second signal line group SG2 may be connected tothe first sensing electrodes EG1 in a double routing structure.

The first sensing electrodes EG1 and the second sensing electrodes EG2may be disposed in the sensing region IS-DA. The first signal line groupSG1, the second signal line group SG2, and the third signal line groupSG3 may be disposed in the line region IS-NDA.

In the embodiment, the input sensing layer ISL may be a capacitive touchsensor which senses an external input in a mutual cap manner. Any one ofthe first sensing electrodes EG1 and the second sensing electrodes EG2may receive a detection signal, and another one thereof may output theamount of change in capacitance between the first sensing electrodes EG1and the second sensing electrodes EG2 as an output signal.

Each of the first sensing electrodes EG1 may be extended along thesecond direction DR2. The first sensing electrodes EG1 may be disposedspaced apart in the first direction DR1. Each of the second sensingelectrodes EG2 may be extended along the first direction DR1. The secondsensing electrodes EG2 may be disposed spaced apart in the seconddirection DR2.

The first sensing electrodes EG1 may include first sensor units SP1 andfirst connection units CP1. The first sensor units SP1 may be arrangedalong the second direction DR2. Each of the first connection units CP1may connect two adjacent first sensor units SP1 among the first sensorunits SP1.

The second sensing electrodes EG2 may include second sensor units SP2and second connection units CP2. The second sensor units SP2 may bearranged along the first direction DR1. Each of the second connectionunits CP2 may connect two adjacent second sensor units SP2 among thesecond sensor units SP2.

The first signal line group SG1, the second signal line group SG2, andthe third signal line group SG3 may be electrically connected tocorresponding signal pads IS-PD. In the line region IS-NDA, a region inwhich the signal pads IS-PD are disposed may be defined as a pad regionIS-PA. A circuit board (not shown) may be connected to the pad regionIS-PA.

FIG. 14 is a plan view of illustrating an enlarged view of region AAcorresponding to FIG. 13 . FIG. 14 illustrates the arrangementrelationship of a first light emitting region PXA-R, a second lightemitting region PXA-B, and a third light emitting region PXA-G. Thefirst light emitting region PXA-R, the second light emitting regionPXA-B, and the third light emitting region PXA-G may be defined the sameas the light emitting region PXA described with reference to FIG. 5 .

Referring to FIG. 14 , in the embodiment, the first light emittingregion PXA-R, the second light emitting region PXA-B, and the thirdlight emitting region PXA-G may have different areas. The first lightemitting region PXA-R may have a first area, the second light emittingregion PXA-B may have a second area, and the third light emitting regionPXA-G may have a third area. The second area may be greater than thefirst area, and the first area may be greater than the third area.

The pixels PX described with reference to FIG. 3 may include a red pixelfor generating red light, a blue pixel for generating blue light, and agreen pixel for generating green light. In the embodiment, the firstlight emitting region PXA-R may correspond to the red pixel, the secondlight emitting region PXA-B may correspond to the blue pixel, and thethird light emitting region PXA-G may correspond to the green pixel.

The first light emitting region PXA-R and the second light emittingregion PXA-B may be alternately arranged along the second direction DR2.Multiple third light emitting regions PXA-G may be provided in anembodiment, and the multiple third light emitting regions PXA-G may bearranged along the first direction DR1 and the second direction DR2. Thefirst light emitting region PXA-R and the third light emitting regionPXA-G may be alternately arranged along the fourth direction DR4. Thesecond light emitting region PXA-B and the third light emitting regionPXA-G may be alternately arranged along the fourth direction DR4.

FIG. 14 illustrates the first light emitting region PXA-R, the secondlight emitting region PXA-B, and the third light emitting region PXA-Gbeing arranged in a pentile form as an example. However, the embodimentis not limited thereto. For example, the first light emitting regionPXA-R, the second light emitting region PXA-B, and the third lightemitting region PXA-G may be arranged in a stripe form. The stripe formmay mean that the first light emitting region PXA-R, the second lightemitting region PXA-B, and the third light emitting region PXA-G arealternately arranged along the second direction DR2, and same lightemitting regions are arranged in the first direction DR1.

Each of the first sensor units SP1 and the second sensor units SP2 (seeFIG. 13 ) may have a mesh shape. The first sensor units SP1 and thesecond sensor units SP2 may each have openings OP-MR, OP-MG, and OP-MB.Accordingly, on a plane or on a plan view, the first sensor units SP1and the second sensor units SP2 (see FIG. 13 ) may not overlap the firstlight emitting region PXA-R, the second light emitting region PXA-B, andthe third light emitting region PXA-G. For example, regionscorresponding to the first light emitting region PXA-R may have firstopenings OP-MR, regions corresponding to the second light emittingregion PXA-B may have second openings OP-MB, and regions correspondingto the third light emitting region PXA-G may have third openings OP-MG.

FIG. 15 is a schematic cross-sectional view of a region taken along lineIV-IV′ of FIG. 14 . The same reference numerals are given to theelements described with reference to FIG. 7 , and the descriptionsthereof are omitted.

Referring to FIG. 15 , the input sensing layer ISL may be disposedbetween the display panel DP and the optical layer OPL-3. The inputsensing layer ISL may include a buffer layer BFL-2, an interlayerinsulation layer IL-C1, and the first sensor units SP1.

The buffer layer BFL-2 may be disposed on the encapsulation layer TFE.The buffer layer BFL-2 may include an inorganic matter. For example, theinorganic matter may be silicon nitride. The first connection units CP1may be disposed on the buffer layer BFL-2. In an embodiment, the bufferlayer BFL-2 may be omitted.

The interlayer insulation layer IL-C1 may be disposed on the bufferlayer BFL-2. The interlayer insulation layer IL-C1 may include aninorganic matter. For example, the inorganic matter may be siliconnitride.

The first sensor units SP1, the second sensor units SP2 (see FIG. 13 ),and the second connection units CP2 (see FIG. 13 ) may be disposed onthe interlayer insulation layer IL-C1. FIG. 15 illustrates the firstsensor units SP1 being disposed on the interlayer insulation layerIL-C1.

The first insulation layer IL1 may be disposed on the interlayerinsulation layer IL-C1. The first insulation layer IL1 may cover thefirst sensor units SP1. The first insulation layer IL1 may have a firstopening OPa-R defined in a region overlapping the first light emittingregion PXA-R. Referring to FIG. 14 , a second opening OPa-B defined in aregion overlapping the second light emitting region PXA-B and a thirdopening OPa-G defined in a region overlapping the third light emittingregion PXA-G are illustrated. A first area of the first opening OPa-R, asecond area of the second opening OPa-B, and a third area of the thirdopening OPa-G may be different from each other on a plane or on a planview. The second area may be greater than the first area, and the firstarea may be greater than the third area.

According to the disclosure, a display device may include a firstinsulation layer having a first opening and having a first refractiveindex, a second insulation layer covering the first insulation layer andhaving a second refractive index greater than the first refractiveindex, a third insulation layer disposed on the second insulation layer,having a second opening, and having the first refractive index, and afourth insulation layer covering the third insulation layer and havingthe second refractive index. Light emitted from a light emitting layerof the display device may be refracted or reflected at the boundary ofeach of the first insulation layer to the fourth insulation layer due tothe refractive index difference, so that a light path may be changed.For example, the light path may be changed in a third direction or in adirection close to the third direction. Due to the changed light path,the light emitting efficiency of the display device may be improved andthe straightness of the light in a front direction may be improved.Accordingly, the display device may have improved light efficiency.

Although the disclosure has been described with reference toembodiments, it will be understood by those skilled in the art thatvarious changes in form and details may be made therein withoutdeparting from the spirit and scope of the disclosure. Accordingly, thetechnical scope of the disclosure is not intended to be limited to thecontents set forth in the detailed description of the specification, butis intended to be defined by the appended claims.

What is claimed is:
 1. A display device comprising: a display panelincluding a plurality of light emitting regions and a non-light emittingregion adjacent to the plurality of light emitting regions; a firstinsulation layer disposed on the display panel, the first insulationlayer having a first refractive index, and having a first openingoverlapping the non-light emitting region; a second insulation layercovering the display panel and the first insulation layer and having asecond refractive index less than the first refractive index of thefirst insulation layer; a third insulation layer disposed on the secondinsulation layer, the third insulation layer having the first refractiveindex, and having a second opening overlapping the non-light emittingregion; and a fourth insulation layer covering the second insulationlayer and the third insulation layer and having the second refractiveindex.
 2. The display device of claim 1, wherein the second insulationlayer and the fourth insulation layer overlap the first opening on aplane.
 3. The display device of claim 1, wherein the first refractiveindex is in a range of about 1.45 to about 1.55, and the secondrefractive index is in a range of about 1.1 to about 1.3.
 4. The displaydevice of claim 1, wherein the first insulation layer and the thirdinsulation layer comprise a first organic matter, and the secondinsulation layer and the fourth insulation layer comprise a secondorganic matter.
 5. The display device of claim 4, wherein the firstorganic matter comprises porous zirconia.
 6. The display device of claim4, wherein the second organic matter comprises a porous acrylic resin.7. The display device of claim 1, wherein a thickness of the firstinsulation layer is in a range of about 1.5 μm to about 5 μm, and amaximum thickness of the second insulation layer is in a range of about3 μm to about 20 μm.
 8. The display device of claim 1, wherein the firstinsulation layer comprises a first through-surface defining the firstopening, and an angle between the first through-surface and the displaypanel is in a range of about 90° to about 120°.